Portable medical imaging system

ABSTRACT

A medical imaging system includes a movable station and a gantry. The movable station includes a gantry mount rotatably attached to the gantry. The gantry includes an outer C-arm slidably mounted to and operable to slide relative to the gantry mount, an inner C-arm slidably coupled to the outer C-arm and, an imaging signal transmitter and sensor attached to the C-arms. The two C-arms work together to provide a full 360 degree rotation of the imaging signal transmitter.

TECHNICAL FIELD

The present invention relates to medical imaging systems.

BACKGROUND OF THE INVENTION

Healthcare practices have shown the tremendous value of three-dimensional imaging such as computed tomography (CT) imaging, as a diagnostic tool in the Radiology Department. These imaging systems generally contain a fixed bore into which the patient enters from the head or foot. Other areas of care, including the operating room, intensive care departments and emergency departments, rely on two-dimensional imaging (fluoroscopy, ultrasound, 2-D mobile X-ray) as the primary means of diagnosis and therapeutic guidance.

While mobile solutions for ‘non-radiology department’ and patient-centric 3-D imaging do exist, they are often limited by their freedom of movement to effectively position the system without moving the patient. Their limited freedom of movement has hindered the acceptance and use of mobile three-dimensional imaging systems.

Therefore, there is a need for a small scale and/or mobile three-dimensional imaging systems for use in the operating room, procedure rooms, intensive care units, emergency departments and other parts of the hospital, in ambulatory surgery centers, physician offices, and the military battlefield, which can access the patients in any direction or height and produce high-quality three-dimensional images.

SUMMARY OF THE DISCLOSURE

According to one aspect of the present invention, a novel medical imaging system is provided. The system includes a movable station and a gantry. The movable station includes a gantry mount rotatably attached to the gantry. The gantry includes a first C-arm slidably mounted to and operable to slide relative to the gantry mount, a second C-arm slidably coupled to the first C-arm and, an imaging signal transmitter attached to one of the C-arms and an imaging sensor mounted to one of the C-arms. The two C-arms work together to provide a full 360 degree rotation of the imaging signal transmitter.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective rear view of an imaging system according to one embodiment of the present invention.

FIG. 2 is a schematic diagram of an imaging controller system 40 according to one embodiment of the present invention.

FIG. 3 is a perspective front view of the imaging system of FIG. 1.

FIG. 4 is a perspective view of the imaging system of FIG. 1 in which the gantry has been rotated about the X-axis by 90 degrees.

FIG. 5 is a perspective view of the gantry partially showing a cabling arrangement.

FIG. 6 is a perspective view of the gantry showing the cabling arrangement.

FIG. 7 is a side view of the gantry showing the cabling arrangement.

FIG. 8 illustrates a motor assembly for telescopically controlling the C-arms of the gantry.

FIGS. 9A-G illustrate the 360 degree rotation of the gantry in 60 degree increments.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of this application, the terms “code”, “software”, “program”, “application”, “software code”, “software module”, “module” and “software program” are used interchangeably to mean software instructions that are executable by a processor. A “user” can be a physician or other medical professional.

FIG. 1 is a schematic diagram showing an imaging system 10, such as a computerized tomographic (CT) x-ray scanner, in accordance with one embodiment of the invention. The imaging system 10 includes a movable station 60 and a gantry 56. The movable station includes a vertical shaft 59 and a gantry mount 58 which is rotatably attached to the vertical shaft. The movable station 60 includes two front omni-directional wheels 62 and two rear omni-directional wheels 64, which together provide movement of the movable station 60 in any direction in an X-Y plane. The omni-directional wheels 62,64 can be obtained, for example, from Active Robots Limited of Somerset, U.K. A pair of handles 13 mounted to the housing of the movable station 60 allow a user to manually maneuver the station.

A motor 66 attached to the vertical shaft 59 is designed to rotate the gantry mount 58 full 360 degrees about the X-axis and a motor 67 moves the gantry mount 58 vertically along the z-axis under the control of the control module 51.

The gantry 56 includes a first C-arm 70 slidably coupled to the gantry mount 58 and a second C-arm 72 which is slidably coupled to the first C-arm. In the embodiment shown, the first and second C-arms 70,72 are outer and inner C-arms, respectively. In the embodiment shown, the outer and inner C-arms 70,72 are circular in shape and rotate circumferentially about a central axis so as to allow imaging of a patient who is lying in bed 16 without the need to transfer the patient.

An imaging signal transmitter 74 such as an X-ray beam transmitter is mounted to one side of the second C-arm 72 while an imaging sensor 74 such as an X-ray detector array is mounted to the other side of the second C-arm and faces the transmitter. In operation, the X-ray transmitter 74 transmits an X-ray beam which is received by the X-ray detector 76 after passing through a relevant portion of a patient (not shown).

In one embodiment, the system 10 is a multi-modality x-ray imaging system designed with surgery in mind. The three imaging modalities include fluoroscopy, 2D Radiography, and Cone-beam CT. Fluoroscopy is a medical imaging technique that shows a continuous X-ray image on a monitor, much like an X-ray movie. 2D Radiography is an imaging technique that uses X-rays to view the internal structure of a non-uniformly composed and opaque object such as the human body. CBCT (cone beam 3D imaging or cone beam computer tomography) also referred to as C-arm CT, is a medical imaging technique consisting of X-ray computed tomography where the X-rays are divergent, forming a cone.

The movable station 60 includes an imaging controller system 40 which serves a dual function of (1) controlling the movement of the omni-directional wheels 62,64, gantry mount 58 and the gantry 56 to position the imaging signal transmitter 74 in relation to the patient, and (2) controlling imaging functions for imaging the patient once the gantry 56 has been properly positioned.

Referring now to FIG. 2, the imaging controller system 40 of the present invention is connected to a communication link 52 through an I/O interface 42 such as a USB (universal serial bus) interface, which receives information from and sends information over the communication link 52. The imaging controller system 40 includes memory storage 44 such as RAM (random access memory), processor (CPU) 46, program storage 48 such as ROM or EEPROM, and data storage 50 such as a hard disk, all commonly connected to each other through a bus 53. The program storage 48 stores, among others, imaging control module 54 and motion control module 51, each containing software to be executed by the processor 46. The motion control module 51 executed by the processor 46 controls the wheels 62,64 of the movable station 60 and various motors in the gantry mount 58 and gantry 56 to position the station 60 near the patient and position the gantry in an appropriate position for imaging a relevant part of the patient.

The imaging control module 54 executed by the processor 46 controls the imaging signal transmitter 74 and detector array 76 to image the patient body. In one embodiment, the imaging control module images different planar layers of the body and stores them in the memory 44. In addition, the imaging control module 54 can process the stack of images stored in the memory 44 and generate a three dimensional image. Alternatively, the stored images can be transmitted to a host system (not shown) for image processing.

The motion control module 51 and imaging control module 54 include a user interface module that interacts with the user through the display devices 11 a and 11 b and input devices such as keyboard and buttons 12 and joy stick 14. Strain gauges 13 mounted to the handles 15 are coupled to the I/O device 42 and conveniently provide movement of the movable station 12 in any direction (X, Y, Wag) while the user is holding the handles 15 by hand as will be discussed in more detail below. The user interface module assists the user in positioning the gantry 56. Any of the software program modules in the program storage 48 and data from the data storage 50 can be transferred to the memory 44 as needed and is executed by the CPU 46. The display device 11 a is attached to the housing of the movable station 60 near the gantry mount 58 and display device 11 b is coupled to the movable station through three rotatable display arms 16, 18 and 20. First display arm 16 is rotatably attached to the movable station 60, second display arm 18 is rotatably attached to the first arm 16 and third display arm 20 is rotatably attached to the second display arm. The display devices 11 a,11 b can have touch screens to also serve as input devices through the use of user interface modules in the modules 51 and 54 to provide maximum flexibility for the user.

Navigation markers 68 placed on the gantry mount 58 are connected to the imaging controller system 40 through the link 52. Under the control of the motion control module 51, the markers 68 allow automatic or semi-automatic positioning of the gantry 56 in relation to the patient bed or OR (operating room) table via a navigation system (not shown). The markers 68 can be optical, electromagnetic or the like.

Information can be provided by the navigation system to command the gantry 56 or system 10 to precise locations. One example would be a surgeon holding a navigated probe at a desired orientation that tells the imaging system 10 to acquire a Fluoro or Radiographic image along that specified trajectory. Advantageously, this will remove the need for scout shots thus reducing x-ray exposure to the patient and OR staff. The navigation markers 68 on the gantry 56 will also allow for automatic registration of 2D or 3D images acquired by the system 10. The markers 68 will also allow for precise repositioning of the system 10 in the event the patient has moved.

In the embodiment shown, the system 10 provides a large range of motion in all 6-degrees of freedom (“DOF”). Under the control of the motion control module 51, there are two main modes of motion: positioning of the movable station 60 and positioning of the gantry 56.

The movable station 60 positioning is accomplished via the four omni-directional wheels 62,64. These wheels 62,64 allow the movable station 60 to be positioned in all three DOF about the horizontal plane (X,Y,Wag). “Wag” is a system 10 rotation about the vertical axis (Z-axis), “X” is a system forward and backward positioning along the X-axis, and “Y” is system 10 lateral motion along the Y-axis. Under the control of the control module 51, the system 10 can be positioned in any combination of X, Y, and Wag (Wag about any arbitrary Z-axis due to use of omnidirectional wheels 62,64) with unlimited range of motion. In particular, the omni-directional wheels 62,64 allow for positioning in tight spaces, narrow corridors, or for precisely traversing up and down the length of an OR table or patient bed.

The gantry 56 positioning is accomplished about (Z, Tilt, Rotor). “Z” is gantry 56 vertical positioning, “Tilt” is rotation about the horizontal axis parallel to the X-axis as described above, and “Rotor” is rotation about the horizontal axis parallel to the Y-axis as described above.

Together with the movable station 60 positioning and gantry 56 positioning, the system 10 provides a range of motion in all 6 DOF (X, Y, Wag, Z, Tilt and Rotor) to place the movable station 60 and the imaging transmitter 74 and sensor 76 precisely where they are needed. Advantageously, 3-D imaging can be performed regardless of whether the patient is standing up, sitting up or lying in bed and without having to move the patient.

Precise positions of the system 10 can be stored in the storage memory 50 and recalled at any time by the motion control module 51. This is not limited to gantry 56 positioning but also includes system 10 positioning due to the omni-directional wheels 62,64.

As shown in FIG. 3, each of the gantry mount 58, outer C-arm 70 and inner C-arm 72 respectively has a pair of side frames 86, 88,90 that face each other. A plurality of uniformly spaced rollers 84 are mounted on the inner sides of the side frames 86 of the gantry mount 58. The outer C-arm 70 has a pair of guide rails 78 on the outer sides of the side frames 88. The rollers 84 are coupled to the guide rails 78. As shown, the rollers 84 and the guide rails 78 are designed to allow the outer C-arm 78 to telescopically slide along the gantry mount 58 so as to allow at least 180 degree rotation of the C-arm about its central axis relative to the gantry mount.

A plurality of uniformly spaced rollers 80 are mounted on the inner sides of the side frames 88 of the outer C-arm 70. The inner C-arm 72 has a pair of guide rails 82 on the outer sides of the side frames 90. The rollers 80 are coupled to the guide rails 82. As shown, the rollers 80 and the guide rails 82 are designed to allow the inner C-arm 72 to telescopically slide along the outer C-arm 70 so as to allow at least 180 degree rotation of the C-arm about its central axis relative to the outer C-arm.

Thus, the present invention as disclosed herein advantageously allows the gantry 56 to rotate about its central axis a full 360 degrees to provide the maximum flexibility in positioning the imaging system 10 with minimum disturbance of the patient.

In another aspect of the present invention, a unique cabling arrangement is provided to make the imaging system 10 more compact and visually more appealing. As shown in FIGS. 5 and 6, a cable carrier/harness 92 contains electrical cables to carry signals between the imaging controller system 40 and various motors, X-ray transmitter 74, imaging sensor 76 and various electronic circuits in the gantry 56. A first cable router 94 is mounted to the outer surface of the outer C-arm 70 and a second cable router 96 is mounted to the outer surface of the inner C-arm 72. Each cable router 94,96 has a through-hole 95,97 through which the cable carrier 92 passes.

The cable carrier 92 extends from the gantry mount 56 over the outer surface of the first C-arm 70, through the through-hole 95 of the first cable router 94 and over an outer surface of the second C-arm 72. The cable carrier 92 overlying the first C-arm 70 extends in a first circumferential direction (clock-wise as shown) 98 and enters the first cable router 94 in a second circumferential direction (counter clock-wise as shown) 99 opposite to the first circumferential direction to create a 180 degree service loop over the outer surface of the first C-arm.

From there, the cable carrier 92 extends in the first circumferential direction 98 and enters the second cable router in the second circumferential direction 99 to create another service loop over the outer surface of the second C-arm 72.

The particular locations of the first and second cable routers 94,96 combined with the service loops allow slack in the cable carrier 92 to provide the gantry 56 with full 360 degrees rotation without tangling or causing stress in the cable carrier. In the embodiment shown, the routers are mounted near the midpoint of the C-arms.

FIG. 8 illustrates one embodiment of a motor assembly 100 that could be used to telescopically rotate the outer C-arm 70 relative to the gantry mount 58 and inner C-arm 72 relative to the outer C-arm. Each motor assembly 100 includes a servo motor 102 with encoder feedback, gear box 104 to change the turning ratio, drive pulley 106, idler pulleys 108 and belt 110 threaded between the drive pulley and the idler pulleys. One motor assembly 100 is mounted to the gantry mount to move the outer C-arm 70 relative to the gantry mount and another motor assembly is mounted to the outer C-arm 70 near the center of the arm to move the inner C-arm 70 relative to the outer C-arm.

FIGS. 9A-9G illustrate the 360 degree rotation of the gantry 56 in the counter-clockwise direction in 60 degree increments with FIG. 9A representing a zero degree position of the imaging sensor 76 and transmitter 74. FIG. 9B represents a 60 degree turn/position of the gantry 56. For each 60 degree turn of the gantry 56, the motor assemblies 100, under the control of the motion control module 51, turn the inner C-arm 72 by 30 degrees counter-clock wise and also turn the outer C-arm 70 by 30 degrees counter-clock wise for a combined 60 degree turn. FIG. 9G represents a full 360 degree turn of the gantry 56. As can be seen, the outer C-arm 70 and inner C-arm 72 have each moved 180 degrees from the original zero degree position of FIG. 9A.

As described above in detail, the present invention in various embodiments provide the following benefits: (1) movement of the system in any X-Y direction with Wag about any Z-axis from the use of omni-directional wheels 62,64; (2) double telescoping C-gantry for full 360-degree imaging beam rotation; (3) imaging while lying in bed, sitting or standing such as standing CBCT; (4) storage and recall of system 10 and gantry 56 positions; (5) quasi-simultaneous multi-planar x-ray imaging; (6) recall of positions via robotics or navigation coordinates.

The foregoing specific embodiments represent just some of the ways of practicing the present invention. Many other embodiments are possible within the spirit of the invention. Accordingly, the scope of the invention is not limited to the foregoing specification, but instead is given by the appended claims along with their full range of equivalents. 

What is claimed is:
 1. A medical imaging system comprising: a movable station; a gantry mount attached to the movable station; a gantry rotatably attached to the gantry mount and including: a first C-arm slidably mounted to and operable to slide relative to the gantry mount; a second C-arm slidably coupled to the first C-arm; an imaging signal transmitter attached to the second C-arms, the first and second C-arms together providing a 360 degree rotation of the imaging signal transmitter; and an imaging sensor mounted to the other side of the second C-arm and facing the imaging signal transmitter, wherein a plurality of uniformly spaced rollers are mounted on inner sides of side frames of the gantry mount; a cable carrier containing a plurality of electrical cables; and a first cable router having a through-hole and mounted to an outer surface of the first C-arm, wherein the cable carrier extending from the gantry mount over the outer surface of the first C-arm, through the through-hole of the first cable router and over an outer surface of the second C-arm.
 2. The medical imaging system of claim 1, further comprising: a controller; and at least three omni-directional wheels attached to the movable station and adapted to be controlled by the controller, the omni-directional wheels providing the movable station with three degrees of freedom (X,Y,Wag) about a horizontal plane.
 3. The medical imaging system of claim 1, wherein the cable carrier extends in a first circumferential direction and enters the first cable router in a second circumferential direction opposite to the first circumferential direction to create a 180 degree service loop over the outer surface of the first C-arm.
 4. The medical imaging system of claim 1, further comprising a second cable router having a throughhole and mounted to an outer surface of the second C-arm, wherein the cable carrier extending through the through-hole of the second cable router.
 5. The medical imaging system of claim 1, further comprising: a second cable router having a through-hole and mounted to an outer surface of the second C-arm, the cable carrier extending through the through-hole of the second cable router; wherein the cable carrier extends in a first circumferential direction and enters the first cable router in a second circumferential direction opposite to the first circumferential direction to create a 180 degree service loop over the outer surface of the first C-arm; and wherein the cable carrier extends in the first circumferential direction and enters the second cable router in the second circumferential direction to create a second 180 degree service loop over the outer surface of the second C-arm.
 6. The medical imaging system of claim 2, further comprising strain gauges mounted to the movable station to allow a user to control movement of the omni-directional wheels under the control of the controller.
 7. The medical imaging system of claim 2, further comprising: a first motor that provides a sliding movement of the first C-arm relative to the gantry mount; and a second motor that provides a sliding movement of the first C-arm relative to the second C-arm.
 8. The medical imaging system of claim 4, wherein the cable carrier extends in a first circumferential direction and enters the second cable router in a second circumferential direction opposite to the first circumferential direction to create a service loop over the outer surface of the second C-arm.
 9. A medical imaging system that provides a 6-degree of freedom movement comprising: a movable station including at least four omni-directional wheels attached to and adapted to position the movable station in all three degrees of freedom (X, Y and Wag) about an x-y horizontal plane; a gantry mount rotatably attached to the movable station; a gantry rotatably attached to the gantry mount and including: a first C-arm slidably mounted to and adapted to slide relative to the gantry mount in a circumferential direction; a second C-arm slidably coupled to and adapted to slide relative to the first C-arm in a circumferential direction; and an imaging signal transmitter attached to the second C-arm, the first and second C-arms together providing a 360 degree rotation of the imaging signal transmitter; an imaging sensor mounted to the other side of the second C-arm and positioned to be facing the imaging signal transmitter, wherein the imaging signal transmitter is capable of moving with respect to the imaging sensor, wherein a plurality of uniformly spaced rollers are mounted on inner sides of side frames of the gantry mount and a cabling system including a first cable router mounted to the outer surface of the first C-arm and a second cable router mounted to the outer surface of the second C-arm.
 10. The medical imaging system of claim 9, further comprising: a controller coupled to the omni-directional wheels; and a joystick mounted to the movable station to allow a user to control movement of the omni-directional wheels under the control of the controller.
 11. The medical imaging system of claim 9, further comprising: a first motor that provides a sliding movement of the first C-arm relative to the gantry mount; and a second motor that provides a sliding movement of the first C-arm relative to the second C-arm.
 12. The medical imaging system of claim 9, wherein the cabling system contains a plurality of electrical cables; the first cable router having a through-hole and mounted to an outer surface of the first C-arm, the cabling system includes a cable carrier extending from the gantry mount over the outer surface of the first C-arm, through the through-hole of the first cable router and over an outer surface of the second C-arm.
 13. The medical imaging system of claim 9, wherein a cable carrier extends in a first circumferential direction and enters the first cable router in a second circumferential direction opposite to the first circumferential direction to create a 180 degree service loop over the outer surface of the first C-arm; and wherein the cable carrier extends in the first circumferential direction and enters the second cable router in the second circumferential direction to create a second 180 degree service loop over the outer surface of the second C-arm.
 14. The medical imaging system of claim 12, wherein the cable carrier extends in a first circumferential direction and enters the first cable router in a second circumferential direction opposite to the first circumferential direction to create a 180 degree service loop over the outer surface of the first C-arm.
 15. The medical imaging system of claim 12, wherein the second cable router having a through-hole and mounted to an outer surface of the second C-arm, the cable carrier extending through the through-hole of the second cable router.
 16. The medical imaging system of claim 15, wherein the cable system extends in a first circumferential direction and enters the second cable router in a second circumferential direction opposite to the first circumferential direction to create a service loop over the outer surface of the second C-arm. 